Answer:
a) In this scenario, the time required for the FP operation would decrease by 20%, which means it would now take 80% of the original duration.

The reduction in this case is 
And the new total time would be calculated as 
b) Here, the overall time is reduced by 20%, indicating that the updated total time would amount to 0.8 times the original total time 
The initial duration for INT operations can be determined as:


For this segment, it is assumed that the INT operations time is the only one adjusted:

And subsequently: 
c) A decrease in overall time suggests the new total would stand at 205 s based on preceding calculations. Timing for FP is now 70 s, for L/S is 85 s, and for INT operations is 55 s. Thus, summing them gives 70+85+55=210 s, indicating that reducing branch instruction times alone cannot lead to a 20% reduction in overall time.
Explanation:
The information shows that a program on a computer is run for 250 s, with 70 s allocated to FP instructions, 85 s for L/S instructions, and 40 s for branch instructions.
Part 1
In this scenario, the required FP operation time diminishes by 20%, indicating it would occupy 80% of the original time.

The reduction in this instance equates to 
And the new total time is given by 
Part 2
<pfor this="" case="" we="" denote="" the="" total="" time="" reduction="" at="" which="" correlates="" to="" a="" new="" of="" times="" original="" cumulative="" src="https://tex.z-dn.net/?f=%20%281-0.2%29%20%2A250s%20%3D200%20s" id="TexFormula12" title=" (1-0.2) *250s =200 s" alt=" (1-0.2) *250s =200 s" align="absmiddle" class="latex-formula">
The original INT operations timing is detailed as:


In this context, we assume the modification pertains solely to INT operations:

And following that: 
Moreover, we can quantify the decline using the proportional change:
in reduction.
Part 3
<pthe decrease="" in="" total="" time="" signifies="" it="" would="" be="" s="" derived="" from="" the="" above="" calculations.="" given="" times="" of="" for="" fp="" l="" and="" int="" operations="" results="" illustrating="" that="" merely="" reducing="" branch="" instruction="" will="" not="" enable="" a="" cut="" time.="">
</pthe></pfor>